Questions tagged [blockchain]

This tag should be used for questions pertaining to the blockchain. The blockchain is a list of all transactions that have occurred using the Bitcoin currency. It consists of blocks which are linked to each other, and each block consists of transactions. DON'T USE THIS FOR THE SERVICE NAMED 'blockchain.info'!

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How do block explorer sites show information that is not available on Bitcoin Core?

As I understood in the following post How to get unspents for a specified bitcoin address?, we should use listunspent only on addresses that belong to our own wallet otherwise will return blank. But ...
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Can't startup Bitgo on Windows [on hold]

After installing bitgoJS, I cd into the bin directory and run the below command bitgo-express --debug --port 3080 --env test --bind localhost I got, 'bitgo-express' is not recognized as an internal ...
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Conditions for recovering a p2pkh bitcoin private key

Apart from Re-using same R value, What are the necessarily ecdsa values needed or method to recover the private key of a p2pkh address. When same address is reused numerous times to receive bitcoin ...
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Loading private key (missing bitcoin)

I exported the private key from a 0.7.2 because I could not how to upgrade the wallet. I then imported it into 0.18.0 I was expecting to see a balance and the transactions and nothing was found. I ...
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1answer
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Error after reindex

Hello after I got an db error.. I try to reindex my db. But I got this error: ERROR: ReadBlockFromDisk: Errors in block header at FlatFilePos(nFile=75, nPos=117947311) So what can I do to fix it ? ...
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Is transaction verification called mining in blockchain? [duplicate]

A transaction in which A sends $10 to B; then this transaction is published in the network. Now, how the other nodes C and D will know, whether A is having $10 or not. and why A should reveal his ...
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Unknown command name and packet magic for bitcoin packets at the start of blockchain transactions

Recently I captured a part of blockchain when my bitcoin wallet started to syncing for the first time. I analyze about 10 Gb of traffic which was for primary transactions of bitcoin. wireshark can ...
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1answer
338 views

Does proof-of-work contribute directly to prevent double-spending?

I know similar questions have been asked before (e.g. How proof of work prevents double spend) but I'm struggling to visualise the solution to double-spending being directly reliant on proof of work. ...
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299 views

Is verification of a blockchain computationally cheaper than recreating it?

One of the advantages of cryptocurrencies like Bitcoin that is often repeated is how hard it should be to manipulate past transactions. The reason that is often stated is that you would have to re-...
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I started build my own blockchain based on mastering bitcoin book using git on win7 and i have a problem

I started learning how to build a blockchain from Antonopoulos book using Git Bash and i have a problem. I used commands: git clone github.com/bitcoin/bitcoin.git cd bitcoin git tag git checkout v0....
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Including transactions in a block - rules and time / technical aspect

I’ve a question regarding block and transactions included in the next block that is solved. Let us assume theoretically that there is newly propagated solved block. And now there are: tx0 and tx1 –...
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Mining Probability

Assuming two miners have a (1/x) chance of finding a block over some time period, is the probability of both miners finding a block within that period simply (1/x^2)? More generally, would n miners ...
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Post Bitcoin mine reward: Lowering Difficulty an Option?

Maybe my understanding of blockchain, and Bitcoin need to be refined and will allow help me understand why my question wouldn't make sense in the grand scheme. But first Ill establish my core ...
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Who is a first miner that receive a transaction from end-user?

This is a First Question. As you already know, the blockchain like Bitcoin, Ethereum is a software program based on peer to peer network system. so I am wondering that who is a first miner that ...
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32 views

Timer-based consensus algorithm in blockchain

Assume that there is an algorithm that ensures: 1- That a full node chooses an honest random wait time. 2- That the same node has waited the specified amount of time before proceeding to mine a block. ...
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How public-key cryptography secures bitcoin transactions from 51% attacks and Mining Attacks

I wanted to better understand how public-key cryptography avoids 51% attacks and mining attacks, also if this question is wrong please correct so that i can improve my research and provide me with ...
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How can a 51% attack be successful? [duplicate]

In the paper by Nakamoto, miner can accept the mined block only if all transaction are valid. Assume that there are 5 miners in the world. 4 of 5 are honest that have 10% of 100% hash power and 1 of ...
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The time when the miner get a new block [duplicate]

I am wondering the time when get a reward for new mined block. Theoretically, miner will earn reward when they mine new block. but at that time, there is no way to verify that they really waste hash ...
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About the balance of specific address

I have a question about how to figure out balance of specific address in the Bitcoin. There are many node in the blockchain(total # of nodes are 10000 based on 01/16/2019). but some nodes may have ...
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1answer
30 views

What is a mechanism of method how to get the data in the blockchain(e.g. bitcoin, ethereum)?

There are websites which have APIs that allow you to trace transactions and lookup information like specific address balances, etc. I am wondering how these web service providers are able to provide ...
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What role does public-key cryptography play in bitcoin transaction? [duplicate]

Explain in one word and kindly tell what is it exactly that public-key cryptography does in bitcoin.
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35 views

What makes Bitcoin transaction secure against attackers/hackers?

Wanted to know what is it that makes bitcoin transaction secure and make it less vulnerable to attackers and hackers
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How to find where coin was picked up

I just recently sent two transactions at $2,500 a piece to a wallet I was given to transfer the money to. The money was transferred and the person has disappeared. I'm wondering how to find out where ...
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38 views

Doesn't an Oracle go against the Blockchain principles?

From what I understand of the blockchain, the main motivation, the very foundation of this technology, is the search for peer-to-peer exchange without mutual trust, without a trusted third party, so ...
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How has the Bitcoin average block size recently risen above 3 MB?

I was aware that the block size could rise above the 1 MB cap due to SegWit. However, my understanding was that the block size would still be limited under SegWit. My understanding of SegWit is that ...
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Why not speed up block mining?

After this question, I have got a question about increase block size: why not reduce the difficulty of PoW? If I understood correctly, this would speed up the mining of the blocks, so we could do more ...
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28 views

What is the need for multiple private keys?

From what I understand, there is initially a seed from which the private keys are derieved and from that the public key respective to each private key is derived. The public key is essentially the ...
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2answers
63 views

download the bitcoin chain begining from a certain date

I am building a bitcoin lightning network using lnd on a separate computer this computer has less than 200G avaible and the actual blockchain is more than 220G, so I am gonna need to use prude mod ...
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BTC Miner, trust? or scam? [duplicate]

trust to miner who after the investment ask You other btc to have free access to unspendable-btc in the wallet? any suggestion?
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How much money in terms of electricity and hardware was invested into blockchain? [closed]

Right now in this moment Thu 11 July 2019 22:08 UK time That's a sizeable number. Almost as big a fraud comitted by a single bank: https://en.wikipedia.org/wiki/Danske_Bank_money_laundering_scandal ...
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Blockchain Private Key

I have been paying amounts of bitcoin, with the promise from Howard Jones in Texas that I will get my private key to get the bitcoin, but when it was time to give me the key, communication went quiet, ...
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2answers
81 views

Convert 33-byte public key with no parity prefix to address

I'm writing a blockchain parser and I keep running into this type of scriptPubKey in the Litecoin blockchain: 20a75ca72ffd994d2004d67b0e89015913f7352455d0111ede590430037c9fe2ac ...
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1answer
22 views

multiple block on the same height?

Just a quick question , in the blockchain api quoting from the documentation it says: get_block_height Get an **array** of blocks at the specified height. Returns an array of Block objects. Params: ...
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1answer
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Doubt regarding hashing function in Merkle trees

From what I read, say in a block, there are 4 transactions. The hash value of transactions A and B are combined together to get the hash AB. Same goes for transactions C and D to get hash CD. Later AB ...
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1answer
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requesting transaction information through peer2peer network got notfound

my current understanding is that after i did my "handshake" with a public node succesfully, i should be able to do a getdata mesage about a transaction from a transaction hash and they should respond ...
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1answer
39 views

Transaction to “dynamic” wallet doesn't arrive?

about one week ago I tried to make a deposit to a service called "escrowbitcommunidad" (some of you might know it). They are using some kind of "dynamic" wallet addresses, meaning each time one ...
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1answer
28 views

Bitcoin transaction stuck

I sent a bitcoin transaction and after sending it I realized that the fee was too low. https://www.blockchain.com/btc/tx/a398c4a2db165bd35435e381a6d185a14aa7a3df40aeca157dd89e4efd2e20d1 in an ...
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1answer
81 views

Finding a transaction in the blockchain [duplicate]

I wanna understand how can a user find a certain transaction he created on the blockchain without him knowing on which block it belongs ? does he have to go over all the blocks using bloom filters to ...
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1answer
26 views

When a new block is propagated, nodes validate from genesis block to propagated block?

For example, I have a nth block and when n + 1 th block is propagated, i have to compare with n+1 block's previous hash and nth block's hash for validation. It is pretty trivial. But do i have to ...
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What are the Advantages of Mainnet over Testnet?

In recent days most of the ICO's starting with test net then developing their own block with mainnet. I don't know why they are doing this. What are the reasons behind this starting with testnet and ...
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2answers
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What would happen if you tried to follow two Bitcoin blockchains from the same computer?

This will probably sound stupid but what would happen if you create an entirely new Bitcoin block chain and run it on the same computer. How does a node know which version of the Bitcoin block chain ...
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2answers
60 views

Does blockchain work like Git?

So the blockchain is a linked list structure, but the transaction chain is a DAG, that means that bitcoin works a bit like Git?
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1answer
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Chicken and Egg confusion over Bitcoin generation

If Bitcoin is rewarded through mining, and mining is the process of packing some transactions in a block(and adding that block successfully to the blockchain), and on the other hand, a transaction ...
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2answers
61 views

I’ll pay whomever can help me Bitcoin Cash from blockchain wallet to Coinbase wallet with Bitcoin address [duplicate]

I've read now a 100 or so questions here with no clearcut answer nor update after they were given advice. I had money in my Bitcoin Cash wallet on Blockchain. I wanted to send the money to my Coinbase ...
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2answers
44 views

How to search for TXs using only the PublicKey linked to those TXs?

The quest is to define a method for searching TXs on the Bitcoin blockchain using only a PublicKey in HEX format - as opposed to searching TXs by popular terms like wallet ID, txid, hash, etc. I ...
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How to validate derivePath for HDWallet?

I am generating addresses for HDWallet while importing account using the Mnemonic Phrase. So I am letting the user enter Mnemonic Phrase and derivePath both. Before generating addresses, I want to ...
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120 views

Missing transaction

I made a transfer on 6/16 from one wallet to another. Despite verification on blockchain.com, the coin is gone from the sending wallet yet never arrived in the receiving wallet. The receiving wallet ...
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can you use blockchain.info instead of hosting bitcoind for a website

If I use api calls to blockchain.info instead of hosting my own bitcoind for checking address values, is it safe?
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Blockchain Payment Has Been Unconfirmed Please Help [duplicate]

Could someone please help me with this trancaction, i sent it via bitmex and not sure how to use fee bump. https://www.blockchain.com/btc/tx/...
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How to check the balance of the list of 1 million Bitcoin Addresses?

How to check the balance of the list of 1 million Bitcoin Addresses? Is there such a program?